1. Field of the Invention
The present invention relates to a mirror device for a vehicle having a mirror surface angle adjusting mechanism of a mirror for viewing a region substantially toward the rear of a vehicle.
2. Description of the Related Art
Generally, a door mirror device for a vehicle has a plate-shaped frame, and is mounted to a vehicle body via the frame. The frame has a mirror surface angle adjusting mechanism. The mechanism main body of the mirror surface angle adjusting mechanism is fixed to the frame, and an inner mirror holder is tiltably supported at the mechanism main body. An outer mirror holder is assembled with the inner mirror holder. The outer mirror holder holds the mirror for viewing the region substantially toward the rear of the vehicle, and covers the side of the mirror which side is toward the front side of the vehicle. Projecting claws are provided at the outer mirror holder. The projecting claws engage with vibration-proofing claws fixed to the frame. Vibrating of the inner mirror holder and the outer mirror holder is suppressed, and chattering of the mirror surface of the mirror is suppressed.
For example, a pair of shaft-shaped rod drives 52 are provided at the mechanism main body of a door mirror device for a vehicle which is illustrated in FIGS. 7 through 9. A thread, at which a groove having a trapezoidal cross-sectional configuration, i.e., concave engagement valleys 54, is formed in a spiral shape, is formed in the rod drive 52. A plurality of the engagement valleys 54 are provided along the axial direction in the peripheral surface of the rod drive 52. The inner mirror holder is held at the distal ends of the rod drives 52.
A predetermined number of claw members 56 are provided at the periphery of the rod drive 52 within a mechanism main body 66. The claw member 56 is elastic. A convex engagement projection 58, which has a trapezoidal cross-sectional configuration, is formed at the distal end of the claw member 56. The engagement projections 58 engage with the engagement valleys 54, and the predetermined number of claw members 56 thereby support the rod drive 52.
A pair of motors (not illustrated) are provided within the mechanism main body. By driving the motors, the predetermined numbers of claw members 56 rotate around the rod drives 52.
Here, when the motors are driven and the predetermined numbers of claw members 56 rotate around the rod drives 52, the claw members 56 move within the engagement valleys 54. Due to the rod drives 52 being moved automatically in the axial direction, the outer mirror holder and the inner mirror holder are tilted, and the angle of the mirror surface of the mirror is automatically adjusted.
Further, when a predetermined tilting force is applied manually to the mirror, the claw members 56 elastically deform, and the engagement valleys 54 ride up over the engagement projections 58, and the rod drives 52 are moved manually in the axial direction. In this way, the outer mirror holder and the inner mirror holder are tilted, and the angle of the mirror surface of the mirror is adjusted manually.
However, in such a door mirror device 50 for a vehicle, as shown in FIG. 7, the angle of inclination of the mirror side surface of the engagement valley 54 with respect to a direction orthogonal to the axis of the rod drive 52, and the angle of inclination of the surface of the engagement valley 54 at the side opposite the mirror side (i.e., the surface of the engagement valley 54 at the side which is further away from the mirror) with respect to the direction orthogonal to the axis of the rod drive 52, are the same, and are both xcex8 (e.g., 30xc2x0).
Thus, a distance L1 (see FIG. 8) in the direction of sliding of the claw member 56 (the engagement projection 58), between a central point A of the base portion (root) of the claw member 56 and a point of abutment B of the engagement valley 54 and the engagement projection 58 at the time when the rod drive 52 is moved toward the side opposite the mirror, is smaller than a distance L2 (see FIG. 9) in the direction of sliding of the claw member 56, between the central point A and a point of abutment C of the engagement valley 54 and the engagement projection 58 at the time when the rod drive 52 is moved toward the mirror. In this way, usually, a load F1 (see FIG. 8), which is applied to the rod drive 52 and which is needed to move the rod drive 52 manually toward the side opposite the mirror, is greater than a load F2 (see FIG. 9), which is applied to the rod drive 52 and which is needed to move the rod drive 52 manually toward the mirror.
If the rigidity of the projecting claws or the vibration-proofing claws is too large, although the ability to suppress chattering of the mirror surface of the mirror can be improved, the resistance (resistance torque) at the time of adjusting the angle of the mirror surface of the mirror is large. Thus, when the rigidities of the projecting claws and the vibration-proofing claws are made to be large, even if an attempt is made to automatically adjust the angle of the mirror surface of the mirror, elastic deformation arises at the claw members 56, and the engagement valleys 54 ride up over the engagement projections 58, and the problem arises that the rod drives 52 cannot move in the axial direction.
When adjusting the angle of the mirror surface of the mirror automatically, in order to prevent the claw members 56 from elastically deforming and the engagement valleys 54 from riding up over the engagement projections 58, the rigidity of the claw members 56 may be made large by increasing the thickness of the claw members 56 or the like. However, if the rigidity of the claw members 56 is made to be large, the loads F1 and F2, which are applied to the rod drive 52 and which are needed in order to manually move the rod drive 52, also become large.
Because F1 is greater than F2 as described above, if the rigidity of the claw members 56 were made large to the extent that F1 were to reach the upper limit value thereof (the limit value at which the rod drive 52 can be manually moved toward the side opposite the mirror), F2 would not reach its upper limit value (the limit value at which the rod drive 52 can be manually moved toward the mirror), and the rigidities of the projecting claws and the vibration-proofing claws could not be made large. (Even if the rigidities of the projecting claws and the vibration-proofing claws were to be made large, when the rod drive 52 was automatically moved, it would not be possible to prevent the claw members 56 from elastically deforming and the engagement valleys 54 from riding up over the engagement projections 58.) On the other hand, even if the rigidity of the claw members 56 was increased to the extent that F2 reached its upper limit value, F1 would exceed its upper limit value, and it would not be possible to move the rod drive 52 manually toward the side opposite the mirror.
Accordingly, the more F1 and F2 can be made to approach the same magnitude, the closer F1 and F2 approach their upper limit values. In this way, the rigidities of the projecting claws and the vibration-proofing claws can be made to be large, and the ability to suppress chattering of the mirror surface of the mirror can be improved. At the same time, the engagement valleys 54 can be prevented from riding up over the engagement projections 58 due to elastic deformation of the claw members 56, at the time when the rod drives 52 are moved automatically. Accordingly, the performances of the door mirror device 50 for a vehicle can be improved.
In view of the aforementioned, an object of the present invention is to provide a door mirror device for a vehicle in which a load, which is applied to a rod member and which is needed in order for an engagement valley to ride up over an engagement projection due to elastic deformation of a claw member such that the rod member is moved toward a side opposite a mirror, and a load, which is applied to the rod member and which is needed in order for the engagement valley to ride up over the engagement projection due to elastic deformation of the claw member such that the rod member is moved toward the mirror, can be made to approach substantially the same magnitude.
A first aspect of the present invention is a mirror device for a vehicle, the device comprising: a holding member for holding a mirror; a connecting member connected to a vehicle body, and for supporting the holding member such that the holding member is tiltable; an elastically deformable claw member which is provided at the connecting member, the claw member having an engagement projection formed at a distal end portion thereof; and a shaft-shaped rod member having at a peripheral surface thereof a valley-shaped groove extending in a spiral shape along an axial direction of the rod member, one end of the rod member being held at the holding member, and the rod member being supported by the claw member due to the engagement projection being engaged with the groove, wherein the groove has a surface at a side toward a mirror and a surface at a side opposite the mirror, and given that an angle of inclination of the surface at the side toward the mirror, with respect to a direction orthogonal to an axis of the rod member, is xcex81, and an angle of inclination of the surface at the side opposite the mirror, with respect to the direction orthogonal to the axis of the rod member, is xcex82, xcex81 greater than xcex82.
The rod member is usually held such that rotation around the axis thereof is not possible. Tilting of the holding member is adjusted in accordance with movement of the rod member in the axial direction. The claw member may be provided substantially parallel to the rod member at a periphery of the rod member. The engagement projection projects toward the rod member, and engages with the groove. The claw member is disposed so as to be rotatable. Due to the claw member being rotated, the rod member is moved in the axial direction. The engagement projection has two surfaces which are a surface, at least a portion of which contacts the surface of the groove located at the side thereof that is toward the mirror, and a surface, at least a portion of which contacts the surface of the groove located at the side thereof that is opposite the mirror. When a load of a predetermined value or greater is applied to the rod member in the axial direction thereof, the claw member elastically deforms, and permits axial direction movement of the rod member.
In the mirror device for a vehicle of the above-described aspect, the holding member, which is tiltably supported at the connecting member connected to the vehicle body, holds the mirror for viewing a region substantially toward the rear of the vehicle. Due to the engagement projection of the claw member provided at the connecting member being engaged with the engagement valley of the peripheral surface of the rod member, the rod member is supported by the claw member, and one end of the rod member is held at the holding member.
Further, the engagement valley is provided due to the groove, i.e., thread mountain (valley), being formed in a spiral shape and extending in the axial direction in the peripheral surface of the rod member. When a predetermined tilting force is applied to the mirror, due to the elastic deformation of the claw member (i.e., because the claw member elastically deforms), the groove (engagement valley) rides up over the engagement projection, and the rod member is moved in the axial direction. In this way, the holding member is tilted, and the mirror surface angle of the mirror is adjusted.
Here, given that the angle of inclination of the mirror side surface of the groove (i.e., the surface of the groove which is nearer to the mirror) with respect to the direction orthogonal to the axis of the rod member is xcex81, and that the angle of inclination of the surface of the groove at the side opposite the mirror (i.e., the surface of the groove which is further away from the mirror) with respect to the direction orthogonal to the axis of the rod member is xcex82, xcex81 greater than xcex82. Thus, the distance in the sliding direction of the claw member (the engagement projection) and between the central point of the root of the claw member and the point of abutment of the groove and the engagement projection at the time when the rod member is moved toward the mirror, can be made to approach, more than is the case in the conventional art, the same magnitude as the distance in the sliding direction of the claw member and between the central point of the root of the claw member and the point of abutment of the groove and the engagement projection at the time when the rod member is moved toward the side opposite the mirror. In this way, the load, which is applied to the rod member and which is needed in order for the groove to ride up over the engagement projection due to elastic deformation of the claw member and the rod member to be moved toward the side opposite the mirror, and the load, which is applied to the rod member and which is needed in order for the groove to ride up over the engagement projection due to elastic deformation of the claw member and the rod member to be moved toward the mirror, can be made to approach substantially the same magnitude.
A second aspect of the present invention is a mirror device for a vehicle, the device comprising: a holding member for holding a mirror; a connecting member connected to a vehicle body, and for supporting the holding member such that the holding member is tiltable; an elastically deformable claw member which is provided at the connecting member, the claw member having an engagement projection formed at a distal end portion thereof; and a shaft-shaped rod member having at a peripheral surface thereof a valley-shaped groove extending in a spiral shape along an axial direction of the rod member, one end of the rod member being held at the holding member, and the rod member being supported by the claw member due to the engagement projection being engaged with the groove, wherein when a load of a predetermined value or greater is applied to the rod member in the axial direction thereof, the claw member elastically deforms, the groove rides up over the engagement projection, and movement of the rod member in the axial direction of the rod member is permitted, the groove has a surface at a side toward a mirror and a surface at a side opposite the mirror, and a relative relationship between an angle of inclination xcex81 of the surface at the side toward the mirror with respect to a direction orthogonal to an axis of the rod member, and an angle of inclination xcex82 of the surface at the side opposite the mirror with respect to the direction orthogonal to the axis of the rod member is determined such that a load, which is applied to the rod member and which is needed in order to move the rod member toward a side opposite the mirror, and a load, which is applied to the rod member and which is needed in order to move the rod member toward the mirror, are substantially a same magnitude.
In the mirror device for a vehicle of the second aspect of the present invention, the relative relationship between xcex81 and xcex82 is set such that the load, which is applied to the rod member and which is needed in order for the groove to ride up over the engagement projection due to elastic deformation of the claw member and the rod member to be moved toward the side opposite the mirror, and the load, which is applied to the rod member and which is needed in order for the groove to ride up over the engagement projection due to elastic deformation of the claw member and the rod member to be moved toward the mirror, are substantially the same magnitude. Thus, the loads applied to the both rod members can substantially be set to upper limit values (limit values at which the rod member can be moved by the groove riding-up over the engagement projection due to elastic deformation of the claw member).
In the mirror device for a vehicle of either the first or second aspect of the present invention, the engagement projection has two surfaces which are a surface, at least a portion of which contacts the surface of the groove located at the side thereof that is toward the mirror, and a surface, at least a portion of which contacts the surface of the groove located at the side thereof that is opposite the mirror. Namely, the engagement projection also has a surface toward the mirror and a surface at a side opposite the mirror. Given that an angle of inclination of the mirror side surface of the engagement projection with respect to the direction orthogonal to the axis of the rod member is xcfx861, and an angle of inclination of the surface of the engagement projection at the side opposite the mirror with respect to the direction orthogonal to the axis of the rod member is xcfx862, xcfx861 greater than xcfx862. By structuring the mirror device for a vehicle in this way, the engagement projection can be made to engage well with a groove which is formed such that xcex81 greater than xcex82.
The mirror device for a vehicle of any of the above-described aspects of the present invention may be structured such that xcex81=xcfx861 and xcex82=xcfx862. In this case, the engagement projection can engage even better with the groove.